The present invention relates to the field of security systems for monitoring and controlling access to a secured or access restricted area, such as a vehicle.
Security systems are in wide use today to control and/or monitor access to secured or access-restricted areas. Such systems typically employ one or more sensors and/or trigger switches which are monitored or controlled by a central controller to sense intrusion or to allow controlled access. Examples of such systems include vehicle security systems and building security systems, which may be activated by either a remote switch or transmitter or by a key pad to enter a predetermined code. Entrance of the correct code typically arms or disarms the system, opens or closes a door or the like. Automotive security systems typically employ vibration sensors, glass breakage sensors, ultrasonic or microwave sensors, as well as triggers such as door, hood or trunk triggers, to detect unauthorized intrusion attempts and to activate alarm devices such as sirens or lights to warn off the intruder and call attention to the intrusion, and in most cases such system will also activate a relay or other electronic circuits disabling the vehicle ignition system.
The sensors and triggers typically detect attempts to intrude into the protected area, such as by way of a door or window, forcing a hood or trunk open, lifting or moving the vehicle or the like. The trigger devices may take the form of switches which are activated by the opening or closing of a door or window. To allow access through doors or other access points, devices which release or position locking elements, such as solenoid switches, are typically employed.
Conventional security systems will not arm when a sensor indicate that a door or window is open, or when a sensor indicates that there is presently an intrusion into the protected area. As an example, a vehicle door left open will typically prevent the security system from being armed, or a window left open in a building will prevent the building security system from being armed. For the same reason, a defective sensor which indicates that a door is open irrespective of the position of the door, i.e., open or closed, will also prevent the security system from being armed. The result is that the vehicle or building owner is deprived completely of the benefit of the security system until the defective sensor is repaired.
Another disadvantage of conventional security systems is repetitive alarm alerts due to conditions such as a defective sensor, or noncorrected or ignored intrusion events. Most systems on the market have a maximum alarm duration for sounding a siren or other noise-making device when an alarm event is detected, after which duration the alarm resets itself. The maximum duration is typically set by local ordinances requiring that alarms shut off after some fixed time, say ten minutes, regardless of whether the owner has attended to the alarm or not. However, if the alarm was caused by a sensor or trigger which remains in an active state after the alarm system resets itself, then successive alarm cycles will be repeated over and over again until the alarm is disabled or the car's battery is depleted.
A further limitation of conventional vehicle security alarm systems is that they typically provide only a single type of audio alarm signal, such as a siren, or a siren sound alternating with a voice-synthesized audio message, e.g., "BURGLAR-BURGLAR." The same audio alert signal is generated no matter why the alarm condition was declared, e.g., a door opening results in the same alarm signal as a vibration sensor alarm condition. In many cases where the sensors cause an alarm, such as a vibration sensor or glass breakage sensor, a real intrusion event follows the sensor alarm condition within a few moments by the thief gaining entry through a door, trunk or hood. Yet because the same alarm audio signal results from both the sensor alarm and the door trigger alarm, the user may simply assume that the sensor alarm has caused the second alarm, not an actual intrusion into the vehicle, and ignore the warning.
Many luxury automobile are equipped with power door locks. Some electronic security and control systems have been integrated with the power door locks so as to automatically lock the doors when the security system is actively armed, and to automatically unlock the doors when the system is disarmed. However, a sitution may arise where an inadvertent activation of the remote control will not only disarm the alarm, but also will unlock the vehicle doors.
It is therefore an object of the invention is to provide a system which does not repetitively cycle through alarm cycles due to a constantly active sensor or trigger device.
An additional object of the invention to provide a security system which provides a different type of alarm signal when a door is opened within a predetermined time interval after a sensor alarm condition is sounded.
A further object of the invention is to provide a security system with passive arming which automatically bypasses active sensor or trigger devices, thereby permitting passive arming to occur even in the presence of defective sensors or triggers and without triggering an immediate alarm.
Still another object of the invention is to provide a vehicle security system having remote control and passive control features with an intelligent automatic locking and relocking function, whereby the system will be passively armed and the doors automatically relocked if a door is not opened within a predetermined time interval after the system is disarmed.